I haven't heard either, although I own a Marantz PM7200 amp which I think is great. It is a couple of generations behind the PM6200.
I think that the only place you can audition both amps is Richer Sounds. They have offered me sale or return in the past, where I can listen at home and return for refund if not happy. I am not sure if they still do this, or indeed if it was a local approach. Ask them because they always seem friendly, irrespective of branch.
Whether buying £250 amp or £2500 amp, I would always recommend listening at home over weekend. This way you can decide at your own pace, and match with your actual gear and to your actual room. The size and shape of room can make a massive difference.
I have never heard a Cambridge amp, but posts here suggested to me a lean clear sound. My Marantz is detailed and bassy, traits I like. If the PM6002 is like the PM7200, I would be really happy with it.
I also have the Marantz CD6002 and think this is really great with a Marantz amp. This does me wonder if the Cambridge Audio CD might be tuned to work with the CA amp. This is all speculation and theory - try at home if you can....it is the only way to make up your own mind.